Sporadic sigmoid colonic angiomyolipoma presenting as a pedunculated polyp: A case report and brief literature review

Angiomyolipoma (AML) is a benign tumor that is commonly found in the kidney. It is composed of blood vessels, smooth muscle, and fat. These mesenchymal tumors are very rarely found in the digestive tract, particularly within the sigmoid colon. We present the case of a 38-year-old female who presented with a four-month history of intermittent left lower quadrant abdominal discomfort, altered bowel habits, and occasional hematochezia. Colonoscopic evaluation revealed a 2.8 cm pedunculated polyp in the sigmoid colon with characteristics suggestive of a submucosal lesion.
Following multidisciplinary discussion, the patient underwent segmental resection of the sigmoid colon. Histopathological examination demonstrated the characteristic composition of AML. Immunohistochemistry (IHC) studies were positive for Melan-A, HMB-45, and smooth muscle actin. The Ki-67 proliferation index was low, and no atypia or necrosis was identified, confirming the diagnosis of AML. 
This case highlights the significance of considering AML in the differential diagnosis of submucosal colonic polyps. Its diagnosis relies on histopathological and IHC evaluation, and complete resection remains both diagnostic and therapeutic.